A highly efficient and versatile synthetic approach for the synthesis of 4-(pyren-1-ylmethyl)-1-(d-glycosyloxy) phthalazine nucleosides 11a,b, 13, β-S-nucleosides 16, 18, 20, and acyclo C-nucleosides 23a,b, 24, 25 and 27a-f was described and fully characterized. Furthermore, a series of desired new nucleoside analogues containing Se of 4-(pyren-1-ylmethyl) phthalazine-1(2H)-selenone 28-33 were synthesized. The structures of all reported compounds were confirmed by IR, 1H-NMR, 13C-NMR, MS and elemental analysis. All compounds have been screened for their antibacterial and antifungal activities. Maximum activity was shown by 20 and 33a comparable to the standard drugs with lower toxicity. The cytotoxicity of the selected compound was measured and evaluated. The energy gap between the highest occupied molecular orbital and lowest unoccupied molecular orbital was calculated using theoretical computations to reflect the chemical reactivity and kinetic stability of the synthesized compounds. Using density functional theory (DFT), electronic parameters such as the highest occupied and lowest unoccupied molecular orbitals (HOMO and LUMO) and the molecular electrostatic potential (MEPS) were calculated. On the basis of different studied structures, these properties were computed in order to elucidate the chemical reactivity and the kinetic stability. Obviously, the band gap energy (Eg) of structures studied reveals that the lowest band gap obtained for the structure 16-a indicates that it has the highest chemical reactivity and lowest kinetic stability.

• Klíčová slova
• S-nucleosides, antibacterial, biocompatibility, mono/disaccharides, nucleoside analogues, quantum calculations,
• MeSH
• antibakteriální látky * farmakologie   MeSH
• ftalaziny farmakologie   MeSH
• kvantová teorie MeSH
• magnetická rezonanční spektroskopie MeSH
• molekulární modely MeSH
• nukleosidy * farmakologie   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• antibakteriální látky * MeSH
• ftalaziny MeSH
• nukleosidy * MeSH

Pichia pastoris is currently one of the most preferred microorganisms for recombinant enzyme production due to its efficient expression system. The advantages include the production of high amounts of recombinant proteins containing the appropriate posttranslational modifications and easy cultivation conditions. α-L-Rhamnosidase is a biotechnologically important enzyme in food and pharmaceutical industry, used for example in debittering of citrus fruit juices, rhamnose pruning from naringin, or enhancement of wine aromas, creating a demand for the production of an active and stable enzyme. The production of recombinant α-L-rhamnosidase cloned in the Mut(S) strain of P. pastoris KM71H was optimized. The encoding gene is located under the control of the AOX promoter, which is induced by methanol whose concentration is instrumental for these strain types. Fermentation was upscaled in bioreactors employing various media and several methanol-feeding strategies. It was found that fed batch with BSM media was more effective compared to BMMH (Buffered Methanol-complex Medium) media due to lower cost and improved biomass formation. In BSM (Basal Salt Medium) medium, the dry cell weight reached approximately 60 g/L, while in BMMH it was only 8.3 g/L, without additional glycerol, which positively influenced the amount of enzyme produced. New methanol feeding strategy, based on the level of dissolved oxygen was developed in this study. This protocol that is entirely independent on methanol monitoring was up scaled to a 19.5-L fermenter with 10-L working volume with the productivity of 13.34 mgprot/L/h and specific activity of α-L-rhamnosidase of 82 U/mg. The simplified fermentation protocol was developed for easy and effective fermentation of P. pastoris Mut(S) based on dissolved oxygen monitoring in the induction phase of an enzyme production.

• Klíčová slova
• Pichia pastoris, fermentation, recombinant enzyme, upscale, α-L-rhamnosidase,
• Publikační typ
• časopisecké články MeSH

Puerarin-7-O-fructoside was transformed by Trichoderma harzianum CGMCC 1523 into 3'-hydroxypuerarin-7-O-fructoside; this was identified by MS and NMR. However, puerarin-7-O-glucoside was not directly hydroxylated but hydrolyzed back into puerarin, which was transformed into 3'-hydroxypuerarin by the same fungi. Comparative analysis of free radical scavenging activity of DPPH showed that the free radical scavenging activity of puerarin-7-O-glucoside was reduced to approximately 1/2 of that of puerarin, while the free radical scavenging activity of puerarin-7-O-fructoside was increased to approximately 1.5 times of that of puerarin. The free radical scavenging activity of 3'-hydroxypuerarin-7-O-fructoside was further increased by 2.2 times of that of puerarin-7-O-fructoside, which was close to that of 3'-hydroxypuerarin.

• MeSH
• biotransformace MeSH
• fruktosa analogy a deriváty   chemie   metabolismus   MeSH
• glykosylace MeSH
• hydroxylace MeSH
• isoflavony chemie   metabolismus   MeSH
• scavengery volných radikálů chemie   metabolismus   MeSH
• Trichoderma metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• fruktosa MeSH
• isoflavony MeSH
• puerarin-7-O-fructoside MeSH Prohlížeč
• scavengery volných radikálů MeSH